No idea why but the Intel pages don't tell you the specific boosts for any processor, I should of put up to 4.7 though in my post not 4.5.
But the per core boosts are:
4,700 MHz (1 core),
4,700 MHz (2 cores),
4,600 MHz (3 cores),
4,600 MHz (4 cores),
4,500 MHz (5 cores),
4,500 MHz (6 cores)...